Counterbalanced door structure



Aug. 12, 1947.

H. A. DAVIDSON COUNTERBALANCED DOOR' STRUCTURE Filed Ndv. 13, 1945)fuman .E .nw A son, 13%' 7).@ M

Patented Aug. 12, 1947 `r UNITED STATES PATENT OFFICEv Herman A.Davidson, Detroit, Mich., assignor to The Aviation Corporation, NewYork, N. Y., a corporation of DelawareV Application November 13, 1945,Serial No. 627,999

3 Claims. (Cl. 126-191) The invention relates to door structures andmore particularly to the type which includes a drop-door adapted to beswung manually into closed, ajar and open positions for use with` ovensor oven-compartments.

One object of the invention is to provide a structure which includes asubstantially vertical counter-balancing pull-spring which appliestorque to the door and to a lever which coacts with a stationarycam-track for holding the door in different positions.

Another object of the invention is to provide an improved structure fordrop-doors, which includes counter-balancing spring-means which requiresrelatively low torque, which is applied through a bell-crank lever tothe door and a track with cams for holding the door in differentpositions.

Other objects of the invention will appear from the detaileddescription.

The invention consists in the several features hereinafter set forth andmore particularly defined by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a vertical section of a portion of a range with a drop-doorstructure embodying the invention, taken through the door adjacent oneof its sides, on line I-I of Fig. 4, the door being closed.

Fig. 2 is a similar section illustrating the door in its open position.

Fig. 3 is a rear elevation of the hinge-structure, illustrating the doorin its closed position, the oven liner being shown in section.

Fig. 4 is a section taken on line 4--4 of Fig. 1.

The invention is exemplified as applied to a range which includes acasing, generally designated 8, and is provided with an opening '9 foraccess to an oven or compartment I and a dropdoor II for closing theopening. The door II is hingedly supported for swinging movements by ahinge-structure which comprises a vertically eX- tending bracket I 4which may be formed of plate metal and is xedly secured in any suitablemanner, for example, by screws I5 to a structural member of the casing 8at one side of the dooropening 9, and a b-racket I9 which also may beformed of plate metal and is xedly secured, in any suitable manner, forexample, by rivets or screws 24 or welding to one of the side edges 20of door Il. The door II is usually formed of sheet metal, with inner andouter walls.V The bracket I4 on the casing is provided with an integralforwardly and downwardly extending arm or member 22, which extendsthrough the pivot-pin 23v to the lower end of the bracket I9 on saiddoor. Pivot-pin 23 between brackets I4 and I9-connects door II to thecasing 8 for vertical swinging movement. Bracket I9 has a shoulder I8which engages a stop-pin I'I carried by bracket I4 to limit openingmovement of door I I and to keep the same in a horizontal position sothat it may be used as a shelf when inserting and removing articles fromthe oven.

The bracket I4 has a curved vertically extending rear edge 26 whichfunctions as a track. Bracket I9 on door I I is provided with anintegral inwardly and downwardly extending arm or member 28 whichprojects from the inner face of the door, and alongside of the side faceof bracket I4. A bell-crank lever-30 is fulcrumed at 3| on the inner endof arm 28 on bracket I9 and includes a downwardly extending arm ormember 32 and an inwardly extending arm or member 34. A roller 36,journalled on a stud 3'I which is mounted on the lower end of arm 32.0fbellcrank lever 30, has a grooved periphery 38 which travels on thetrack 26 on the inner edge of stationary bracket I4. A pull-spring 40`has its lower end 4I connected, in any suitable manner, to a fixed partof the casing 8 and its upper end connected, as at 42, to the inner endof arm 34 of lever 30. l

The track 26 is provided with a cam or hump 44 adjacent its lower endand a cam or hump 48 adjacent its upper end, over which the roller 36will ride. The cam 44, when the door is swung aJ'ar or to a partly openposition, operates as an abutment for roller 36 to which yielding torqueis applied through lever 30. by spring 40 to hold the door ajar near itsclosed position. Cam 48 operates, when the door is being swung towardits horizontal position, as an abutment for roller 36 to yieldingly holdthe door II against movement into horizontal position to prevent a sharpimpact when the door reaches horizontal or way openfposition which wouldtend to break the hinges or clip the enamel parts, and as an abutmentfor roller 36 which is pressed by spring 48 against the track 26 at theupper end of said cam for resisting upward movement of the door when ithas reached its horizontal position.

The operation'will be as follows: during swinging movement of the dooron the axis of pivotpin23, it will move fulcrum pin 3| for the bellcranklever 30 in an are concentric with said axis. Assuming the `door isclosed, roller 36 will be positioned at the lower end of the cam 44 ontrack 26. Yielding torque applied by spring 40 to arm 34 of lever 30,will press roller 36 against the lower portion of cam 44 and the latterwill resist movement of the door from its closed position. The yieldingtorque provided by spring 40 and applied to fulcrum pin 3l will thenalso assist in holding the door in its closed position. During theinitialY opening movement of the door, the manual force applied theretowill swing a"rri`128v on bracket I9 to raise' lever 36, aridwill,throughv fulcrum pin 3|, cause roller 36 to ride Yover cam 44.

passed over cam 44. The yielding torque applied ,10, When it is desiredto hold the door ajar, the'4 Voperator will release the door when roller36 has;Y

j door opening,adoor for closing said opening, hinge to lever by spring40 will then-,hold roller 36* against track 26 at the upper end Yo'fcani 447, which will arrest the bodily downward movement of lever 36 andhold roller 36 so that' the further upward movement of the door will bearrested, Y

The door will then be held lajarY or' in aV partly open position. Whenit is,l desired., to lower the. doorrto its horizontal position, l'itwill be' swung? downvvardlyV androllerf3r6; will ride on' track26;

be held by the yielding torque app1id1tdlver'30' by spring aufs@ tliajtthe dobr'vviu kie/,held in: its

horizontal position 'y andY the shoulder I 8 against stop-pinI I1.

.'1` e spring 4`UVeXt`e'nds'approiimately inl` a vertical Vdirct'in to`eiert a vertically Ydownviard vpull on ari'njill of vleyer1f3llndapplies yielding torque to said lever/which is fiilcruind on arm`28'Vsothat roller A36 will be Vyie'li'ingly"pressed'against track 26andyielding torque willbe appliedthroilgh 4ful-- rum p'insito'coiiteifbalaficetiie doer.

vD'lllring 'th'e' 7 lowering niovei'neritV of" .the- "door, spring", 4Uwill b'e'nexter'ded t'of progressively in`- crease the magnitude f itscirque;d Toy prevent an undesirable increase" "orN esilienttp'rquop'pcs' ing the lowering" movnent of the? door" as Yitfap'`` proachesits lowered'position', cam-'track 2'6'islo`f eccei'itr'i 'contigui'relatively t@ rv1 -piii` :aw-ith' lessfceiiticity at tlifpperfend'of'tlie track and greaterV eccntiicita't its lower endl! Dur: ing theswinging movements of thedoon'the di` rection of pull o`f spring/40'reiiia'ins approiinfiate-v ly Yv'e'rita/.ll ',Ifhisis V dsirable YS"0`that' it iS Ilot necessary't extend the sp-iing'tithe' rear' po'rtio'n'of the/overl'. This'coristruct'ionprovides a co'uhterebalance'd door',which rifio've's smoothly during its swinging riivmerits'vwhilethe cams44' andil on trani; 26 serv'asabutmeiits against which rou; er 3`6 isprssdfo'r holdingY the door in it'sopen, ajair and'lqwieu'positions;' Y

The ccuriterlcalariced hinge-structure is illustratejti at oii'e" sideof the4 door, but may', yif d'- sii'd, b'aDIiefd tbotli S'dS.If'iis'ed'at-Oil Side' onliiiingpe-brackets mand I9A and pivot-cinesiwithout the ciiteiltalaiieiiig anu holding mechanism; arpreviueq at theopppsitesideof italia ioi.r A Y The Vinvintiii exemplifies acounter-balanced do-swtliu adapted fbi' OVrd0rS,`WhiCh iSsimpleincons'triictin; which'results' in swing# irrgmovements or thedoar, anu which includes avrtically'extendirg earn-'trackan'dabellecrank lever carrying a roller' for? engaging the track, which'are adapted'ior usewith a vertically exe tending 'puni-spring adjacentthe Yfr'ontv of the brackets rigidly mounted on th'e casing and door,

respectively, andpivotally connected for swinging movement of the door,the bracket on the door having an inwardly projecting arm, the bracket`onvthe casing having a vertically extending curved track with cam-meanson its inner edge, a bellcrank lever fulcrumed on the inner end of thearm on the bracket -on the door, having a downwardly extending' armprovided with means for engaging' the' track' andi an 'inwardlyextending' arm; anda spring between the inwardly extending arm ontlilever'and thecasiri'g' for xer'tingyielding torque to swing the leverto' engage' the track and to" exert lifting torque :onlthe door?.

4 A" door'structure comprising, fa casi'n'g'h'avingA adooropning, a doorfor closing said opening,

hinge brackets rigidly mounted onfthe casing and door, respectively, andp'iv'oftallyv connected for swinging movement ofthe door, tliebracket onthe YdoorY having an inwardly projecting arm, the bracket on the casing"liav'ingfa';V vertically" e'ii'- tending curved trackwith caiiifmeaii'son its'inrier edge, a bell-crank lever fulcrurned' o'n the inner end fthe vari'nronY the' blackty on the door', provided Witli aVro'lleroii'a. downwardly XtI-idii'ig portion thereof for4 engaging thevtrack-,Tandai spring cciriiie'cteu to the lever? inwardly` or" theroller and to thev casing/for" exerting yielding torque to swing the'lever'to h'old/therller engageu witii'the track and to'exertliftirigftrqu on the door. Y Y f l 3. A door structure comprisiiig`,acasi'ng'having a door opening, a door for closing said' cpe'iiing, hingebrackets rigidly'iiiqurited en' the casing'aiid cloni,l respectively,and: pivc't'allyi connected'- for swinging" movement of' tiie door', thebraeketfn the'doo'r having anI inwardly projecting arm', the bracket onthe casingliz'ivingray vertically extending curved track withcam-nie'r'is orfit's inner edge, a lever frulcrum'ed' onth'einner endo'f't'he arm on the bracket on the door, and provideuwitli means belowthefulcrumfr 'engaging' th'e track,v Y

and a spring connected tthe lever inwardly of the fulcrum'for exertingyielding torque' to swing the lever'to engage't'hetrack'and toexe'rtalift ing torque'onthe door.

